How to strengthen chain link

[a64pilot]

Originally Posted by RaymondR

Cross cut the ENDS of the links.

Fit them together.

Fully penetrate weld them with a low hydrogen rod.

Sleep tight.

G43 chain has I believe a tensile strength of 58,000 PSI.
The exceedingly common low hydrogen rod that is used everywhere is 7018.
The first two digits of welding rod denote it’s tensile strength, so any rod with the first two digits of 70 has a tensile strength of 70,000 PSI.
I would not use 6010 or 6011 as it’s a very porous weld.

https://www.lincolnelectric.com/en-u...ns-detail.aspx

Been 40 or so years ago but I used up to 110,000 PSI tensile strength low hydrogen rod in the oil patch when was a welder back then.
So done properly the weld joint is stronger than the chain, and will feed smoothly.

I would use 7018 myself. Probably 3/32 or 1/8 rod.

G70 chain is heat treated to make it stronger, welding G70 will change the heat treat on the welded links, my guess is that it would weaken then to G43 level.

[Jim Cate]

^^^^

For Ray and A64 above: all very well if you happen to be a certified (or even just expert amateur) welder with available equipment, but for the common cruiser, this isn't often a viable method of joining chain, simply because of availability of equipment and skill. And transporting several hundred pounds of chain off to a welding shop, should there be one nearby, is awkward without a vehicle, and if one is at anchor, it may be difficult to find one's boat when you return with your longer chain!

The simple C-link has saved our bacon more than once when we've had to cut chain when faced with a fouled anchor or rode. It's simple to do immediately, right on the foredeck, and really, if you are not pushing the limit on chain strength (and few of us really do this in practice), the minor loss in ultimate strength is not a worry.

Like Breaking Waves posted above, we've used such joiners ever since we sailed from SF in 1986. None have broken, and we've weathered our share of crappy wx in crappy anchorages. Chain failure is a vanishingly rare event in the cruising world and I feel that we here on CF spend far too much time worrying about it. The safety factors encompassed in the SWLL numbers allow for a lot of degradation in the chain before it becomes the limiting factor in anchoring (if you have properly sized the chain for your vessel).

I know that many will view the above as heresy, and it is only an opinion... but one based on a bit of experience and the numbers in the tables.

Jim

[Simi 60]

Originally Posted by RaymondR

Take it to a welding shop and get it welded.

Easy if light and not much chain and are dirt based with a car
Different story when living on water, no car and using 13mm or bigger and 80m lengths

[Simi 60]

I imported a box of rated forged 13mm acco/peerless links made in Japan
Claim to be stronger than 13mm grade L
When I use them I will sikaflex the halves together to keep moisture out
And use a soft shackle as backup.

https://www.peerlesschain.com/products/440840802.html

[Simi 60]

Originally Posted by Pete7

John, does this article help?

C-links – Cox Engineering

Good article, I spoke to Viv online before going the Acco/peerless route.

[chrisr]

Originally Posted by Jim Cate

^^^^

For Ray and A64 above: all very well if you happen to be a certified (or even just expert amateur) welder with available equipment, but for the common cruiser, this isn't often a viable method of joining chain, simply because of availability of equipment and skill. And transporting several hundred pounds of chain off to a welding shop, should there be one nearby, is awkward without a vehicle, and if one is at anchor, it may be difficult to find one's boat when you return with your longer chain!

The simple C-link has saved our bacon more than once when we've had to cut chain when faced with a fouled anchor or rode. It's simple to do immediately, right on the foredeck, and really, if you are not pushing the limit on chain strength (and few of us really do this in practice), the minor loss in ultimate strength is not a worry.

Like Breaking Waves posted above, we've used such joiners ever since we sailed from SF in 1986. None have broken, and we've weathered our share of crappy wx in crappy anchorages. Chain failure is a vanishingly rare event in the cruising world and I feel that we here on CF spend far too much time worrying about it. The safety factors encompassed in the SWLL numbers allow for a lot of degradation in the chain before it becomes the limiting factor in anchoring (if you have properly sized the chain for your vessel).

I know that many will view the above as heresy, and it is only an opinion... but one based on a bit of experience and the numbers in the tables.

Jim

the perfect solution is often not available to us in the real world...esp cruisers. we make do with the best we can at the time eg the C link

cheers,

[Mike Banks]

They are plenty strong if you braze them. Not if you do not. Brazing using silver brazing rod and the proper flux is not difficult at all. A portable propane torch will do it easily. Some rods come coated with their own flux, but I like to buy it in a jar and keep my rods bare.

I never tested the brazed links, but I did snap a chain once towing a truck out of a bog using a D4--and it was an ordinary link that broke at the pressure weld, not the brazed link. It just pulled apart and opened out--but that is not likely on a mooring chain. All of the links except the oversize joining bifurcated brazed link were deformed, the chain completely overloaded . I have no idea what the strain was--but it was considerably more than any vessel at anchor would be likely to impart.

With standard chain, all links are welded. With some special chains at least every second link is welded, usually pressure forged when white hot in an induction furnace. Sometimes all the links are done in this way. Only alternate links can be drop forged in one piece. The days of cast iron or cast steel chains are long over for smaller vessels. It is all made from drawn low alloy or mild steel or stainless steel bars now.

The only way to match or exceed that existing link strength is with a slightly larger diameter link with a long diagonal cut, and a brazed join. I would not trust them with the join un-brazed. I also do not trust other types of links EXCEPT a moused Keystone link, and I use them only when I need to add nylon warp to an all chain rode quickly. I have the nylon already spliced to a short length of chain, it is a temporary job, and I mouse the links shut. Keystone links are drop forged and extremely strong, but they have to be moused shut so they have no chance of ever opening. They will not open as long as they at re under load.

Silver brazing, by the way, is quite adequate for the purpose. It is how large band saws in sawmills are joined, and the joins flex as the band passes over the large driving and idling pulleys. They have tremendous tension loads on them when sawing a log. Silver brazing properly done will easily hold a chain link splice together if done properly.

[Mike Banks]

These riveted DROP FORGED connectors are fine. They are adequate and I have used them for logging chains with no problems. They are not cheap though. There are others I would not be using that look the same, but are rubbish, so buy them with care.

The only way they could conceivably fail is if the chain is severely twisted while under heavy load--and that is not likely if there is a swivel anywhere in the chain rode. I always use an oversized swivel close the the anchor itself. Usually half a metre or less away from the shaft.

The reason I use the other type of bifurcated connector is because I believe them to be stronger, not because these riveted joiners are not adequate for most anchoring. Lets face it, the snubbing cleats would tear out of the decks of most vessels before such a quality riveted connector broke on a straight pull.

[RaymondR]

I change sections and weld rejoin them when I do my annual slip and antifoul and have never had a problem finding someone around the slipyard to do the welding. It's generally about a half carton job in Australia.

The reason that I cross cut the ends of the links is that I can slightly overbuild the weld without it causing problems going around the winch, the chain parts working on each other where the gals burned off keep the rust off and, very importantly, the welded join is under shear loading on two surfaces rather than tensile.

[Mike Banks]

I was told by my ship chandler NOT to use 316 stainless steel anchor chain, it was only used by commercial vessel on their nets to hold the bottom of the nets close to the sea bed, not for heavy loads.

So I bought the heavy galvanized chain and isolated the windlass bus-bars when not in use. Five years later is was still OK.

[Simi 60]

Originally Posted by Mike Banks

They are plenty strong if you braze them. .

And how does that stick to the galvanizing?

[model 10]

Originally Posted by Simi 60

And how does that stick to the galvanizing?

Brazing takes place at a temp above the temp that melts galvanizing. By the time you got a flow of brazing rod, the galv coating would be gone. Brazing is the best glue for most metals.

[Nicholson58]

If the OP is running three strand to his chain then the split link (assume Crosby, not look alike junk) is probably stronger than the rope. The best is to replace the chain and sleep better. Jedi’s link is certainly strong enough but I know it wouldn’t pass my wildcat. BTW, I have seen that link sold in chandleries in stainless. I looked up the specs. It’s butter.

[s/v Jedi]

Originally Posted by Nicholson58

If the OP is running three strand to his chain then the split link (assume Crosby, not look alike junk) is probably stronger than the rope. The best is to replace the chain and sleep better. Jedi’s link is certainly strong enough but I know it wouldn’t pass my wildcat. BTW, I have seen that link sold in chandleries in stainless. I looked up the specs. It’s butter.

So what is different with your wildcat? You have a horizontal windlass?

[Manateeman]

Greetings. Welding or brazing galvanized material without complete understanding of the danger involved can cause serious medical injury.
Do not do this unless you have all the proper equipment and experience. A lot of trained welders refuse to touch galvanized material. Not just zinc fumes but lead.
Please leave this to professionals.
The risk of serious and permanent personal injury is not to be taken lightly.
Mark